抄録
A serial Nitrification-Denitirfication Process (O-AO-O Process) which utilizes organics incorporated into bacteria as the main carbon source for denitrification, has been recently developed as a nitrogen removal process from domestic wastewater. More than 80% of nitrogen can be removed from wastewater by the O-AO-O Process without nitrified-liquor recirculation, hence it can save enrgy. However, it requires comparatively long Hydraulic Retention Time (HRT), ca. 20 to 24 hours, in the biological reactors. The objective of this study is to develop a process which can cut required HRT of the present O-AO-O process by half. A 165L pilot plant was fablicated and experimental studies on nitrogen removal from domestic wastewater were carried out from June 1992 through May 1993. Polypropylene pellets were added up to 40vol.% of the oxic-tank in order to enhance nitrification, and effects of immobilizing pellet and ORP on denitrification were investigated. Whereas the water temperature in the reactors fell as low as 12.5°C, 65% of the influent nitrogen was removed within 13.2 hours of biological reaction time.
